U.S. Pat. No. 245,762 to Armstrong describes a packing for a rod or valve-stem formed with solid metal rings or wires stacked in a circumferential direction around a valve stem. Various diameters are used to fill the voids between the wires. This stack of metal wires is encapsulated in a fabric. The packing structure is placed in a packing housing that surrounds a central shaft.
U.S. Pat. No. 779,480 to Johnston describes a metallic packing made of metal balls that fills an annulus between a valve stem or shaft and a gland. The balls are made of babbitt material, and the dead space between the balls is filled with graphite and oil lubricant. The balls are preloaded against the shaft using a simple spring and plug arrangement.
U.S. Pat. No. 895,037 to Noble is concerned with forming a packing for a rod. A seal is constructed with a white-metal grease impregnated core made in a ring configuration to seal a rod. The core is wrapped with layers of textile made of nickel-spring steel. The structure is finally wrapped with one or more layers of asbestos cloth. Under compression, the grease squeezes out to help seal and lubricate the piston rod.
U.S. Pat. No. 3,020,185 to Moffit Jr. et al describes a seal constructed of a compressible wire core covered by a wire-mesh fabric sheath which are then covered by polytetrafluoroethylene outer sheathing element. The seal is to be used as a static seal in the fire walls of jet engine aircraft to prevent leakage of moderate temperature gases under normal circumstances and to serve as a fire-break under emergency conditions.
U.S. Pat. No. 3,180,564 to Fuhrmann et al describes a radial seal used to seal or separate adjacent cavities of a Wankel or rotary type engine. The sealing elements are thin walled metal tubes that are formed into rectangular, bar-like sealing elements. A filler material, which is most commonly sand, is used during flattening operation to prevent flattening distortions or collapsing of the tube. Depending upon the embodiment, this filter material may or may not be left in the rectangular shaped tube. The sole purpose of the filter material when left in the seal is to prevent the thin-walled tube from collapsing due to operating loads. This filler material in no way impedes gas flow through the seal.
U.S. Pat. No. 4,219,203 to Bellavin et al is directed to a seal that is constructed of an aluminua silica batting core covered by a knitted metallic wire with a ceramic fiber sleeve braided snugly thereover. Surrounding the ceramic fiber sleeve is an outer covering of ceramic or glass fabric at least a portion of which is coated with a pressure sealing material.
U.S. Pat. No. 4,441,726 to Uhl describes a seal constructed by several approaches, depending on the operating temperature. For high temperature operation of about 1260.degree. C. the inner core of the seal is made of dense Inconel wire mesh covered next with an intermediate cover made of a braided ceramic sleeve, which is followed by an outer wrap made of an Inconel double braided wire mesh hollow sleeve.
U.S. patent application Ser. No. 292,146 which was filed by the NASA administrator on Dec. 30, 1988, and issued as U.S. Pat. No. 4,917,302 on Apr. 17, 1990 is directed to a high temperature flexible seal. Stacked wafers having their major surfaces substantially parallel to the direction of potential leakage are preloaded in the axial direction to minimize leakage therebetween. Pressure is applied to the wafers to form a seal between a moveable panel and an adjacent sidewall.